Add MasterView.has_rows concept and related logic

Now the `BatchMasterView` no longer provides most of these goodies.

Also tweak some custom batch views to reflect changes etc.

tailbone/templates/themes/better/base.mako

@@ -42,7 +42,7 @@
               % if master.listing:
                   <span class="global">${model_title_plural}</span>
               % else:
-                  ${h.link_to(model_title_plural, index_url, class_='global')}
+                  ${h.link_to(index_title, index_url, class_='global')}
                   % if master.viewing and grid_index:
                       ${grid_index_nav()}
                   % endif